(1) Field of the Invention
This invention relates to a drive apparatus for varying the speed of a scanning system for use with copying machines, which utilize variations in scanning speed to change the magnification of the reproduced image.
(2) Description of the Prior Art
It is common in optical copying machines to place a document upon a transparent support platen and to transfer an image of this document by incrementally scanning the document. By varying the rate at which the document is scanned, an enlarged or reduced copy of the document can be produced.
U.S. Pat. No. 4,035,075 to Charles G. Sprado assigned to Minnesota Mining and Manufacturing Company, shows a scanning system which may be adapted to produce variable magnification copies. The scanning system of Sprado is driven by one cam. The chief advantage of cam drive means associated with moving scanning carriages is close control over the position, velocity and acceleration of the carriages which results in a reduction in vibration and shock associated with carriage movement.